The post and beam joints are the mechanics that hold a Heavy Timber Frame or Round Post and Beam home together. Without these integral parts the structure would either be held together with metal plating or it wouldn’t be held together at all. In some homes, instead of using the timber shell for the superstructure, instead the home is built conventionally and then timber accents are installed.
Within a Heavy Timber Frame home all of the timbers are usually made from Douglas Fir. The logs are flattened and formed into the square timbers. Now the joinery should be explored.
One of the most complete and comprehensive resources for the technical information on this style of homes can be found in the Timber Home Living magazine. I have several issues in our library. The timber joints all have special names depending on their location and how they are made within the frame.
The Mortise and Tenon joint is one of the most common. This is where the square end of one fits into the slot of another. Here we see this joint built into a round log king truss.
The mortise and tenon interlock. Here is this log truss finished.
Another joint is the dovetail. This one looks just like then end of an expensive dresser drawer. It is wider and the base and narrower at the center. The dovetail prevents a timber from sliding out of the joint.
Also employed with timber framing are knee braces. Here is a post with a knee brace on each side. The post serves to hold the over head beam. Then the knee braces help to prevent any lateral movement while also being attractive to look at.
This square header beam is being support by a rough sawn post with a knee brace on each side. The knee bracing has a decorative notch and holes carved into it.
One major difference I noticed between the timber homes advertized in the Log Home Living magazine and the timber homes featured in the Timber Home Living publication is the timber homes in Log Home Living are often companies which offer glu-lam beam homes. The ones in the Timber Home Living are almost always solid log timbers– n0t glue-lam.
So do your homework as you shop for you heavy timber home. Take time to investigate what type of wood — glue-lam or solid wood– the company is supplying you with. Take notice of what type of joinery is going to be used or if the company is offering metal plating. And also be sure to see if the timbers come precut and ready to fit together or are they just a stack of random timbers that you have to fit together on site. For our Heavy Timber Frame Homes we use a CNC machine to fully precut the timbers before they arrive on the job site. We also can offer a few different finishes to the surface of the timbers.